Artificial turf

Artificial turf, or synthetic turf, is a grass-like man-made surface manufactured from synthetic materials. It is most often used in arenas for sports that were originally or are normally played on grass, however, it is now being used on residential lawns and commercial applications, as well.

1960s and 1970s

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Close view from a water-based field hockey artificial turf

David Chaney -- who moved to Raleigh in 1960 and later served as dean of the North Carolina State University College of Textiles -- headed the team of RTP researchers who created the famous artificial turf. That accomplishment led Sports Illustrated magazine to declare that Chaney was the man "responsible for indoor major league baseball and millions of welcome mats." Artificial turf first came to prominence in 1965, when AstroTurf was installed in the newly-built Astrodome in Houston, Texas. The use of AstroTurf and similar surfaces became widespread in the 1970s and was installed in both indoor and outdoor stadiums used for baseball and gridiron football in the United States and Canada. Maintaining a grass playing surface indoors, while technically possible, is prohibitively expensive, while teams who chose to play on artificial surfaces outdoors did so because of the reduced maintenance cost, especially in colder climates with urban multi-purpose "cookie cutter" stadiums such as Cincinnati's River front Stadium, Pittsburgh's Three Rivers Stadium and Philadelphia's Veterans Stadium.

1980s and 1990s

Some football (soccer) clubs in Europe installed artificial surfaces in the 1980s, which were called plastic pitches (often derisively) in countries such as England. In England several professional club venues had adopted the pitches, QPR's Loftus Road, Luton Town's Kenilworth Road, Oldham Athletic's Boundary Park and Preston's Deepdale until the English FA banned them in 1988. Artificial turf gained a bad reputation on both sides of the Atlantic with fans and especially with players. The first artificial turfs were a far harder surface than grass, and soon became known as an unforgiving playing surface which was prone to cause more injuries (and, in particular, more serious joint injuries) than would comparatively be suffered on a grass surface. Artificial turf was also aesthetically unappealing to many fans.

In 1981, London soccer club Queens Park Rangers dug up its grass pitch and installed an artificial one. Others followed, and by the mid-1980s there were four plastic grass pitches in operation in the English league. They soon became a national joke: the ball pinged round like it was made of rubber, the players kept losing their footing, and anyone who fell over risked carpet burns. Unsurprisingly, fans complained that the football was awful to watch and, one by one, the clubs went back to natural grass. [1]

In the 1990s many North American soccer clubs also removed their artificial surfaces and re-installed grass, while others moved to new stadiums with state-of-the-art grass surfaces that were designed to withstand cold temperatures where the climate demanded it. The use of artificial turf was later banned by FIFA, UEFA and by many domestic football associations, though, in recent years, both governing bodies have expressed an interest in resurrecting the use of artificial surfaces as the related technologies continue to evolve (see below 21st century).

21st century

In the early 21st century, new artificial playing surfaces using sand and/or rubber infill were developed. These "next generation", or Artificial Grass, surfaces are often virtually indistinguishable from grass when viewed from any distance, and are generally regarded as being about as safe to play on as a typical grass surface — perhaps even safer in cold conditions.

Many clubs have installed the new synthetic turf surfaces (most commonly as part of an all-weather training capability), while some clubs which have maintained grass surfaces are now re-considering artificial turf. With football clubs in Europe looking to reduce both maintenance costs and the number of winter matches that are cancelled due to frozen pitches, the issue has also been re-visited by that sport's governing bodies.

The Scottish Premier League banned synthetic pitches for competition matches in 2005, following a two year experiment by Dunfermline Athletic who installed XL Turf, made by Swiss company XL Generation. The management of Dunfermline were happy with the surface, but the league banned the use of the artificial pitch due to complaints by visiting clubs (particularly Rangers and Celtic).

"The most common type uses polyethylene "grass" about 5 centimetres long, which is lubricated with silicone and sewn into a rubberised plastic mat. The whole thing is then "infilled" with a 4-centimetre layer of sand and rubber granules, which keeps the fibres upright and provides the right level of shock absorbency and deformability. The majority of the 15 or so turf manufacturers approved by FIFA use this technology.
The other sort, typified by Dunfermline's pitch, has a base of expanded polypropylene, a foamy material originally developed as a shock absorber for the car industry (see diagram). The grass is also made of lubricated polyethylene fibres, but they are shorter and more densely packed than on an infilled pitch, and are also interspersed with short, curly, spring-like fibres that keep the blades upright. The finishing touch is an 8-millimetre filling of rubber granules." [2]

According to FIFA [3], the installation at the Borussia-Park in Mönchengladbach is another major step in the quality and development of artificial turf surfaces.

UEFA have since announced that starting in the 2005-06 season, approved artificial surfaces will be permitted in their competitions.

Field hockey

The introduction of synthetic surfaces has significantly changed the sport of field hockey. Since being introduced in the 1970s, competitions in western countries are now mostly played on artificial surfaces. This has increased the speed of the game considerably, and changed the shape of hockey sticks to allow for different techniques, such as reverse stick trapping and hitting. Due to the cost of installing synthetic pitches, India and Pakistan have lost their once dominant position in international competition.

Field hockey artificial turf differs from soccer and football artificial turf in the way that it does not try to reproduce a grass 'feel', being made of shorter fibres similar to the ones used on Dunfermline's pitch. This shorter fibre structure allows the improvement in speed brought by earlier artificial turfs to be retained. This development in the game is however problematic for many local communities who often cannot afford to build two artificial pitches: one for field hockey and one for other sports. The FIH and manufacturers are driving research in order to produce new pitches that will be suitable for a variety of sports.

The different categories of pitches include:

Unfilled pitches (often called "water-based" pitches): The pile is unfilled. The pitches require wetting, hence the name "water-based", often via prolonged showering with pitch-side water cannon prior to their use and occasionally during half-time intervals depending on the prevailing atmospherics. They are favoured by most sports since they offer more protection for players by minimising the abrasive effect created by the sand. These pitches form the majority of the elite level field hockey pitches in use today.
Sand-dressed pitches: the pile of the carpet is filled to within 5-8 mm of the tips of the fibre with fine sand. The sand cannot be seen. It can be confused with unfilled pitches.
Sand filled pitches: the pile of the carpet is filled almost to the top with sand. The sand makes the pitch rough and harder. In comparison to water-based pitches or minimal sand-dressed pitches, ball speed across the surface is often noticeably slower.

Applications

Since the late 1990s, the use of synthetic grass has moved rapidly beyond athletic fields to residential and commercial landscaping artificial lawns. This trend has been driven primarily by two functions: the quality and variety of synthetic grasses that are available has improved dramatically, and cities and water conservation organizations have begun realizing the value of artificial grass as a conservation measure.

Advantages and disadvantages

Advantages

Artificial turf can be a better solution when the environment is particularly hostile to natural grass. An arid environment or one where there is little natural light are examples.
Ideal for holiday homes when maintenance of lawns is not practical. It is also a solution for elderly homeowners who find the upkeep of lawns too much hard work.
Suitable for roof gardens and swimming pool surrounds.
Artificial turf pitches can last up to 10 years. That is much longer than natural turf, and their toughness makes them more suitable for multi use stadia.
Some artificial turf systems allow for the integration of fiber-optic fibers into the turf. This would allow for lighting or advertisements to be directly embedded in a playing surface, or runway lighting to be embedded in artificial landing surfaces for aircraft. Forbes article about fiber-embedded artificial turf.

Disadvantages

The rubber infill can get in shoes very easily.
Some artificial turf requires infill such as silicon sand and/or granulated rubber made from recycled car tires. This material may carry heavy metals which can leach into the water table. The granules can also produce a distinctive odor which is considered to be unpleasant.
Needs to be disinfected periodically due to the fact it does not absorb body fluids in the same way as natural turf (although the belief that artificial turf harbours infection has recently been contested by academics[4])
Turf toe is a medical condition which is often associated with playing on artificial turf pitches.
Friction between skin and some types of artificial turf causes abrasions and/or burns to a much greater extent than natural grass. This is an issue for some sports: for example, soccer in which sliding maneuvers are common and clothing does not fully cover the limbs.
Artificial Turf tends to be much hotter than natural grass.

External links

FIFA guidelines for artificial turf PDF
New Scientist article
English Football Association guidelines for choosing artificial grass pitches
Turf toe, a general introduction
Use of rubber and environmental considerations. This article discusses new technology which is planned to mitigate some of the problems of using recycled car tyres (tires). It also quantifies the amount of rubber on a typical pitch as 100 tons or 22,000 old car tyres.
Rubber pollution in a domestic environment. This article looks at the impact of rubber crumb on a domestic environment.
Artificial Turf for Soccer: a technical overview 2007
Artificial Turf for Soccer: Testing and Requirements FIFA-EN-DIN; an Overview